A 3-D conductivity model of the Australian continent using observatory and magnetometer array data

Liejun Wang, Adrian P. Hitchman, Yasuo Ogawa, Weerachai Siripunvaraporn, Masahiro Ichiki, Kiyoshi Fuji-Ta

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

An exploratory 3-D model of the electrical conductivity structure of the Australian continent is presented. The model is derived from the inversion of vertical magnetic-field transfer functions from the Australia-wide Array of Geomagnetic Stations. Crustal conductivity anomalies evident in the model are consistent with those previously mapped by independent magnetometer array studies and new electrical structures are suggested in the upper mantle. The model represents a seamless continent-scale basis for further models likely to be derived from subsequent studies. The model reveals three upper-mantle enhanced-conductivity anomalies beneath Archaean cratonic regions and two upper-mantle anomalies beneath Phanerozoic terranes in eastern Australia. Two of these anomalies have been investigated by recent magnetotelluric (MT) surveys, one in the Yilgarn Craton-Officer Basin-Musgrave Block the other in the Gawler Craton region, and are consistent with the MT results. Across much of central Australia enhanced conductivity at depths of 50-100 km is observed in the model. This region corresponds well with a recognized seismic velocity gradient at 75-100 km. Conductivity differences are also observed beneath Archaean cratons in Western Australia. The Pilbara Craton is represented as an enhanced conductivity anomaly at about 100 km, corresponding well with the lowervelocity anomaly evident in surface wave tomography models. The Yilgarn Craton is imaged as a low-conductivity body, with conductivity two orders of magnitude lower than the Pilbara Craton, continuing to greater depths.

Original languageEnglish
Pages (from-to)1143-1158
Number of pages16
JournalGeophysical Journal International
Volume198
Issue number2
DOIs
Publication statusPublished - 2014 Jul

Keywords

  • Cratons
  • Crustal structure
  • Geomagnetic induction
  • Magnetic and electrical properties

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

Fingerprint Dive into the research topics of 'A 3-D conductivity model of the Australian continent using observatory and magnetometer array data'. Together they form a unique fingerprint.

Cite this